My [53 F] daughter [26 F] is living with a couple, my husband is upset

We are a mid western couple, happily married for 30 years. My husband retired this summer with good savings and a house. I work part time at a library mostly for fun. We are happy and content.We have only one daughter. She got good grades, did not cause any trouble, attended good schools, got admitted into an MBA school and works in NYC. She is also very beautiful girl.She recently visited us and we had a good family time. She told us that her job is good and she was living alone in an apartment in Manhattan. She was helping my husband set up some program that stores files on the internet on his iPad. My husband has trouble loosing pen drives with files and pictures. She setup the program and was showing him how to share picture folders with her. She shared some folder with him.My daughter was out for drinks with her friends. My husband was looking at what she shared and he stumbled on some pictures that were very lewd. My daughter was basically having sex with a man and a woman who seem to be a couple. There are pictures of her with him and her alone or with both of them. There was a short video too which seems to have been taken in the kitchen with my daughter having sex with the husband while the wife is filming it. There are pictures of them lying around in what appears to be an affluent house semi clothed.My husband is practically distraught and he is saying that he failed himself as a father. I am upset but more concerned for my husband and do not know how to broach this with my daughter.Edit: We have been extremely shocked and we just had our mouths open when we scrolled through the pics. We did not check it multiple times. It is just that it has been running in our heads ever since. I called up my daughter and asked her to unshare her folder which she did right away. I told her that we saw one pic where she was lying naked on the floor. She asked me if I saw anything else. I told her that we stopped looking after seeing that picture.Edit: Those people whoa re saying we shouldn't have looked. It is complicated because my husband doesn't know too well on how to use tech. He is 61 and he just started a slideshow of her folder. It had lot of general pictures and videos of NYC central park etc. Thena t the end there were these pictures. The video was like for 15 seconds. He did not see other pictures. He only saw the video. I saw the pictures to understand the scope of the issue as my husband was very distraught as soon as the video appeared.tl;dr: Husband upset after finding daughter is living with a couple via /r/Parenting http://ift.tt/2ewM0wN